No description available.

Thesis (M.S.)--University of Wisconsin, 1964. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (p. 39-43).

The development and calibration of both a plane-headed (hemi-spherical view), and a spherical-type heat flux meter has been undertaken in this work. These instruments have been shown to be capable of producing a signal which is directly proportional to the incident radiant heat flux. Both radiant heat flux meters developed in this work, make use of a radial disc, conductivity type sensing element, where the incident radiant energy is distributed radially via the disc to a cooled metal block. The metal block heat sink is located at the end of a water-cooled arm to enable insertion into high temperature environments. Transient response analysis of the plane-headed heat flux meter yields a time constant of 10. 6 seconds. A perturbation analysis of the spherical heat flux meter concluded that the response time is a function of the radiation heat transfer coefficient existing between the probe and its environment. A finite difference analysis has been carried out on the radial disc assembly in order to investigate the temperature distribution under steady state conditions. It has been concluded that the mode of attachment of the radial disc assembly onto the cooling water probe, can have a modifying effect on the magnitude of the heat meter signal. However, this effect does not introduce non-linearity into the steady state signal response. For the finite difference analysis, an empirical correlation has been derived describing the convective heat transfer at a plane surface with the flow of cooling water perpendicular to the surface. The correlation applies for annular flow, and is given as: Nu = 1. 045 Re0. 4 Pr1/3 Testing of the spherical heat flow meter has been carried out in a 440kW gas-fired furnace. It has been concluded from these trials that: (i) a peak signal output is obtained for an equivalence ratio, o of between 1. 15 and 1. 32, in the range of firing rates 118kW to 142kW, where o is defined as. (ii) the ceramic shield, which forms an integral part of the heat meter, did not develop cracks or physical defects during the trials, (iii) the peak signal from the heat meter closely follows the peak heat gain by the furnace cooling water load rather than the optimum combustion conditions, as indicated by the flue gas composition. A steady state mathematical model of the gas-fired furnace is presented here, and is compared with the results obtained from the furnace runs. This is the first stage in the development of an unsteady state furnace model for use as an aid in the testing of furnace control systems.

No description available.

No description available.

Thesis (doctoral)--Freie Universität Berlin, 2004. / "April 2004"--P. [2] of cover. Lebenslauf. Includes bibliographical references (p. 182-[199]). Also available on the World Wide Web.

Heat transfer and fluid flow characteristics for natural convection of air in a vertical parallel channel system have been examined. The results of both theoretical and experimental work are reported in this thesis. The system of differential equations governing the fluid flow was solved using the PHOENICS code program. The PHOENICS solution gave velocities, temperatures and pressures throughout the field and velocity and temperature profiles are presented at different vertical locations for three channel heights, 1,2 and 3 m, each for three different channel widths, 50,100 and 150 mm. A further PHOENICS sub-routine was written to obtain relevant dimensionless parameters such as the Nusselt Number, which characterises the heat transfer to the air, the Rayleigh Number, the dimensionless air flow rate and dimensionless channel length. The results obtained have been compared with experimental results and with existing data for channels with constant wall temperatures. Non-isothermal wall cases were also considered and the resulting velocity and temperature profiles are presented. The channel used in the experimental work was formed from two vertical plates, one of which was electrically heated, while the other was glass. Heated plates of height 1m and 2m were used and combination of these formed a plate of height 3 m. The width of the plates was 1 m. A double glazed cover plate of the same dimensions could be adjusted to give spacings between the heated plate and glass from 25 mm to 150 mm. The electrically heated plate could be controlled to give the required constant plate temperature (range 35-125°C) and heating could be augmented by a solar simulator consisting of 50 Tungsten Halogen Lamps of 150 Watts each. From the experimental results, relationships between the Nusselt number, Rayleigh number, dimensionless air flow rate and dimensionless channel height have been obtained. In addition, the effect of diffuser sections at the channel inlet and outlet and transient operating conditions were investigated experimentally. Effects of atmospheric pressure and humidity were also considered. The experimental results are compared with those from the PHOENICS solution and with existing data for constant wall temperature conditions and they show good agreement. A discussion of the use of the correlating equations for the heat transfer coefficient and air flow rate in the design of passive solar heating systems, such as the Trombe wall, is also included.

No description available.

No description available.

Thesis (M.S.)--Oregon Graduate Institute of Science and Technology, 1990.